All earthen wells, over time, whether oil or water wells, become degraded, usually in a manner that severely decreases a well""s production rate. This degradation typically results from clogging of the well""s perforated casing and gravel (filter) pack. This clogging is the result of naturally occurring chemical precipitates, such as calcium carbonate or silica, and gelatinous masses produced by iron-secreting bacteria, or other toxic and non-toxic anaerobic bacteria that are in the groundwater. These clogging deposits restrict the oil or water from entering the perforated casing, significantly reducing well performance, and increasing corrosion and encrustation of the casing and screens.
Previous attempts to solve these clogging problems have been difficult and expensive. In most cases, removal of the well""s pump is required to allow complete access into the well. After the removal of the pump, the well can be treated using appropriate chemical and mechanical techniques. However, even these measures do not assure success, and often it is necessary to drill a completely new well. In any event, these measures are costly and difficult, and the use of chemicals and mechanical cleaning devices can easily result in damage to well casing and screen sections. The cost of pump removal alone can easily run into tens of thousands dollars.
Surprisingly little effort has been devoted to investigating the benefits of well maintenance programs. The use of appropriate well maintenance programs would improve well performance and extend well life. This neglect is probably due to additional program costs, and the fact that changes in this industry are not easily effected.
In the past, some water wells had small-diameter metal pipes welded to the outside of the casing. These small diameter pipes normally extended only to the top of the well screen and to below the location of the well pump. Pressure transducers or measuring tapes could be inserted into these pipes to monitor changes in water levels without interfering with the pump. However, these pipes provided no means for cleaning the well.
The present invention solves many repair problems associated with clogged water wells. The invention allows easy and complete access to the exterior of the well casing, screen, and gravel pack where clogging originates. Over time, regular scheduled use of the invention can significantly improve well performance and reduce pumping costs. Current repair efforts are inefficient because they require first that the well pump be removed, and second that the interior of the well screen be cleaned. Both of these functions are laborious and time consuming.
It is therefore an object of the present invention to provide apparatus and method for the clearing of clogs from water wells.
It is another object of the present invention to provide apparatus and method capable of cleaning and disinfecting wells.
It is another object of the present invention to provide apparatus allowing direct access to the exterior surfaces of the gravel pack, well screen, and casing of a water well so that they can be efficiently cleaned and disinfected.
It is a feature of the present invention that well pumps and other surface equipment do not need to be removed from the well in order for cleaning and disinfecting of the well to be accomplished.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the foregoing and other objects, and in accordance with the purposes of the present invention, as embodied and broadly described herein, the apparatus of this invention comprises least one perforated casing situated adjacent to an outside surface of a water well casing having a top and a bottom, the at least one perforated casing extending from a first position at the top of the water well casing to a second position at the bottom of the water well casing. 3. In another aspect of the present invention, and in accordance with its purposes, a method of cleaning a water well comprises the steps of installing at least one perforated casing adjacent to an outer surface of a water well casing having a top and a bottom, the at least one perforated casing extending from the top of the water well casing to the bottom of the water well casing, and forcing appropriate chemicals and surfactants through the at least one perforated casing to clean the water well.